Democratic presidential candidate Hillary Rodham Clinton waves as she steps onstage before speaking at Trident Technical College during a campaign stop, Wednesday, June 17, 2015, in North Charleston, S.C. David Goldman/AP hide caption

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Black Lives Matter activists confronted Democratic candidates Martin O'Malley and Bernie Sanders at a Netroots Nation event earlier this month. O'Malley used the phrase "all lives matter" twice, which he later apologized for. Ross D. Franklin/AP hide caption

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Gray Barrett (right) took this selfie with Rand Paul in Washington, D.C., this summer. "Though I'm not a Rand Paul supporter, I couldn't pass up this opportunity!" he said. Courtesy Gray Barrett hide caption

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Supporters of Democratic presidential candidate Sen. Bernie Sanders, I-Vt., cheer at a campaign rally in Portland, Maine. Sanders is packing 'em in: 10,000 people in Madison, Wis.; more than 2,500 in Council Bluffs, Iowa; another 7,500 in Portland. Robert F. Bukaty/AP hide caption

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Republican presidential candidate and TV personality Donald Trump arrives by escalator to the tune of "Rockin' in the Free World." Musician Neil Young did not approve of his song choice. Brendan McDermid /Reuters/Landov hide caption

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Former U.S. Secretary of State Hillary Clinton Ethan Miller/Getty Images hide caption

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